Progress in FY2012 was in the following areas: 1. INVESTIGATIONS OF FUNCTIONAL AMYLOIDS. We have completed solid state NMR studies of Pmel17 fibrils, reported to facilitate melanin polymerization within mammalian melanosomes. The NMR data show that only about 30% of the Pmel17 repeat-domain sequence participates in the Pmel17 fibril core, and that the core structure is highly polymorphic. 2. LOW COMPLEXITY SEQUENCES. We have initiated a collaboration with the Prof. Steven McKnight of UT Southwestern to apply solid state NMR and electron microscopy to studies of homo- and hetero-association of proteins that contain low complexity sequence (LCS) domains. A wide variety of LCS-containing proteins, some involved in mRNA export and localization of gene expression, have been identified in Prof. McKnight's lab and implicated in formation of intracellular granules that appear to be comprised of amyloid-like fibrils. Electron microscopy and preliminary solid state NMR measurements indicate that detailed molecular structural characterization will be feasible in FY13.